#define _CRT_SECURE_NO_WARNINGS 1
#pragma warning(disable:6031)


//https://leetcode.cn/problems/peak-index-in-a-mountain-array/
class Solution {
public:
    int peakIndexInMountainArray(vector<int>& arr) {
        int left = 1, right = arr.size() - 2;

        while (left < right)
        {
            int mid = left + (right - left + 1) / 2;

            if (arr[mid] < arr[mid - 1]) right = mid - 1;
            else left = mid;
        }
        return left;
    }
};